Climate mediates continental scale patterns of stream microbial functional diversity.

Area of Science:

• Microbial ecology
• Biogeography
• Ecosystem science

Background:

• Understanding microbial functional diversity is key to predicting climate change impacts on global ecosystems.
• Research on microbial functional biogeography, particularly in freshwater systems, is limited.
• This study investigates functional genes in stream biofilm microbes across elevational gradients in Norway, Spain, and China.

Purpose of the Study:

• To investigate large-scale patterns of microbial functional diversity in stream biofilms.
• To determine the influence of elevational gradients and climate on microbial functional gene assemblages.
• To project future changes in microbial diversity under climate change scenarios.

Main Methods:

• Analysis of 15,289 functional genes from stream biofilm samples.
• Comparison of microbial functional gene diversity and composition along elevational gradients.
• Statistical modeling to identify climate and non-climatic predictors of diversity patterns.

Main Results:

• Microbial alpha diversity decreased with increasing elevation, and assemblage composition showed greater turnover over larger elevational distances.
• These patterns were consistent across different mountains, kingdoms, and functional gene categories.
• Climate variables, such as temperature and precipitation, were the primary drivers of microbial functional gene diversity at both mountain and continental scales.

Conclusions:

• Climate significantly controls microbial functional gene diversity in streams at large spatial scales.
• Stream ecosystem processes are sensitive to climate variations, particularly at high latitudes.
• This research provides a framework for anticipating ecosystem responses and biogeochemical feedbacks to climate change.